Commercial heating, ventilation and air conditioning (HVAC) units, such as aptly named “rooftop units,” are often assembled onto the flat roofs of structures such as supermarkets, office buildings and other commercial structures.
Chillers, or chilled water units, are cost-effective systems that utilize both water or other suitable liquids and refrigerants. Chillers cool the water or other liquid, then circulate the cooled water to other components in the system, such as an air handling unit. Chillers are typically located in equipment rooms such as in basements or at other remote locations of large buildings. Water is an excellent secondary coolant because it is readily available, inexpensive, non-toxic and substantially non-corrosive. It also has a favorable specific heat value. Other secondary coolants can also be used, depending upon the application. These include calcium chloride or sodium chloride brines, methanol, propylene glycols, ethylene glycol and glycerin. Chillers are frequently used for commercial air conditioning and industrial process cooling as well as for low temperature refrigeration. While there are various types of chillers, which may include many different components, a chiller typically includes a compressor, a motor and a control center, which may be in the form of a microprocessor control. A chiller can also include, in addition to the above equipment, a condenser, an evaporator and a metering device.
Due to their sometimes difficult-to-reach locations, servicing chillers and rooftop units can be time consuming and inefficient, particularly if a service technician must make multiple trips to diagnose and later return with proper parts to effect a repair. However, most current methods of monitoring the operation of chillers, rooftop units of air conditioning systems, or other HVAC systems do not provide the capability to diagnose an existing problem or anticipate the occurrence of a problem that could result in shut down or improper operation of equipment and to arrange for that problem to be repaired.
What is needed is a system for monitoring an HVAC system that utilizes information from the control center of the unit to automatically identify a malfunctioning part causing a problem, place an order for that part, and dispatch a service technician to install the replacement part upon its arrival.